In the comments from the backpedalling article

4) What remains unexplained is why/how there can be a hockey stick in tree growth when there is no corresponding hockey stick in the local temperature measurements. That’s right — the LOCAL temperature record does not show a hockey stick. So we are supposed to think these trees are responding to some sort of global average temperature and not to local temperatures? Try thinking about that one for a while.

Is that true?
Then what is the use of the tree ring data?